Bolts or Rivets?

Collected two 5ft knives for my newly purchased mower. Every section save two needs replacing. Should I rivet them as per standard or change over to bolts? I have always used rivets in the past, but have never needed to refit an entire knife with new sections at one time. Any advice appreciated. Pictures of knives as found attached.
SadFarmall

I've found bolts much easier to work with. But, you'll likely need the high arch hold down clips as standard clips don't usually have the clearance for the nuts. Good luck.

It's an on-going war. Some guys hate rivets, some
guys despise bolts.

My situation is probably not common. I mow about a hundred acres a year with the sickle mower, stuff that most people would use a bush hog on. Because of this I probably do more repair and maintenance on my knives than most. I also mow hay with a Hesston 1091, on ground with a lot of stone, which tears up the bar as well.

I use both bolts and rivets. I have a Sickle Servicer, so the rivets go in easily, and I carry an old Hesston tool on the tractor so I can replace knives in the field if necessary. I would rather use bolts on the head if possible, because they are easier to get tight, and to remove if I break a knife there.

Rivets are cheaper, seem to be two types available, black finished ones are softer and easier to form, but shear off easier if you hit something. Plated rivets are harder and hold up better, but you are more likely to break a knife than shear the rivet.

On the Hesston, I use all bolts, but they don't work quite right. If I use the high arch fingers they fill up with grass, because the bolt head is not tall enough to keep them cleared. If I use the low arch they don't quite clear the bolt head and it wears away. I am tempted to go back to rivets on that as well.

The bolts I have bought lately do not seem as hard as they used to be. I have to be very careful not to wring them off when I tighten them. I usually hammer them in to the bar so I don't have to strain them by pulling them in with the nut.

I am going to have to do that to some McCormick mower knives, a No. 9 and a Big 6,I am going to use rivets as they have worked fine for me for 50 years and see no reason to change to something that to me has obvious problems in that those rivet heads will catch and drag and then the hold downs sticking up way to far would also cause problems.

I am going to have to do that to some McCormick mower knives, a No. 9 and a Big 6,I am going to use rivets as they have worked fine for me for 50 years and see no reason to change to something that to me has obvious problems in that those rivet heads will catch and drag and then the hold downs sticking up way to far would also cause problems.

I used to prefer rivets...till I bought a swather with bolts.Now that's all I use.

A couple of years ago, rebuilt a 7ft knife on our John Deere 39N sickle mower.

Replaced all new sections and used rivets.

<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/39N%20Mower/?action=view¤t=IMG_0011.jpg" target="_blank"></a>

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<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/39N%20Mower/?action=view&amp;current=IMG_0043.jpg" target="_blank"></a>

Takes a little longer, but that was the way the knife was designed.

Maybe some day I'll get around to our McCormick 7ft sickle mower.

<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/McCormick/?action=view&amp;current=IMG_0996.jpg" target="_blank"></a>

I have found out that when installing bolts you can warp the sickle bar. It stretches the hole that is how it can warp it. After using bolts it will enlarge the rivet hole so can't go back to using rivets.

Better to just buy the entire sickle new.

"Every section save two needs replacing"

Aw heck, go ahead and replace those two while you're at it. You'll regret it if you don't.

I like rivets. You might have to change the hold down clips if you switch to bolts.

If they need changed anyhow. . .

I agree with 12251 - bolts are a lot easier but on my Ford 501 mower I had to use the high-arch hold down clips to provide clearance for the bolt heads.

Quick and easy.

Tom in TN

From what I see of the knife bar I think you better replace the whole knife....and probably the guards and hold downs while you're at it if you want it to cut right.
As far as bolts/rivets go... I prefer bolts... but that does come back to wether or not you have the right hold downs for them. They are higher...
In all honesty I try to avoid sickle bar mowers at all costs. Disc mowers make life easier here...

Rod

I think that what matters is how you plan on using the mower. If
you are restoring the mower to take to shows I would use the rivets
as the bolts would look out of place. If you are going to use the
mower use the bolts. Bolt on sections are much easier to change in
the field and they are faster. We keep a few sections in the cab
along with a wrench to remove the guard and a wrench for the nuts
that hold the sections on. With the guards that we use we would
have to remove the guard to change a section with either rivets or
bolts. No rivets in the cab, no rivet changing tool.

My late older brother was using one of those horse drawn mowers that had the 5-foof bar and he got too close to the fence row. The cutter bar caught on a sapling and the tongue broke.

The horses were not injured and we got them unhooked. My dad wasn't too happy and I told him farm work is dangerous. I used the 10-20 to pull the mower back to the machine shed. Later on I sawed off the tongue and made some brackets. I used a brace and bit to drill the holes didn't have an electric drill. I bolted the brackets on the tongue and used the 10-20 to pull the mower. I stopped and picked up my dad and we went out and mowed alfalfa. When they ordered a new Farmall H they bought a 7-foot sickle bar mower. Too bad we didn't have a 7-foot horse drawn mower like the one shown in your picture. Hal

On a sickle bar mower I would go back with the rivets. The High arch hold downs catch grass and cause them to plug more. I have a very good NH 451 mower I switched it to bolts. In grass that has the short under growth all it would do was plug up. On tall coarse grass it did fine. So I switched it back to rivets when I changed the sections the next time.

Thanks for all the replies. I have both high arch and standard knife clips here, so can easily fit either type. I like the thought of using bolts on the knife head because it is awkward to rivet, but I have one concern, which may be totally unfounded. When you rivet a section into place, the shank of the rivet swells to fit tightly in the knife-back. This means there is little or no possibility of it moving and slogging out the hole, whereas a bolt must be sufficiently narrow to fit through the holes in both section and knife-back. If a bolt were to come loose it could (I think?) damage the knife. Has anyone had such an occurrence or am I worrying about nothing?
SadFarmall

Spent a little time on this mower to free the knife, but not much else.

Cut a little bit of grass to just to see if it was still working.

The photo below shows some of the grass hanging on the cutter bar.

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One of the previous owners made what appears to be an aluminum pitman.

Previous owner also installed a handle under the pan seat to move it around.

The tongue is in good shape and included some of the hardware to harness the mules.

I use both, depends on what I've got on hand. And when I've run out of nuts, the bolts have become rivets...